Process of developing photographic pictures.



sium carbonate are introduced.

UNITED STATES Patented August 18, 1903.

PATENT OFFICE,

FRIEDRICH FISCHER AND HUGO GUNTRUM, OF ELBERFELD, GERMANY, ASSIGNORS TO FARBENFABRIKEN ELBERFELD 00., OF NEW YORK, I N. Y., A CORPORATION OF NEW YORK.

PROCESS OF D EVELOPING PHOTOGRAPHIC PICTURES.

SPECIFICATION forming part of Letters Patent No. 736,374, dated August 18, 1903. Application filed February 20, 1903. Serial No. 144,332. (No specimens.)

on so u is especially suitable for developing photographic pictures. The production of the said amidooxybenzyl sulfonic acid is described in a separate application for Letters Patent, filed February 20, 1903, Serial No. 144,332.

In carrying out the new process practically we can proceed as follows: Six grams of sodium sulfite are dissolved in one hundred cubic centimeters of water, and into the resulting solution one gram of m-amid o-o-oxybenzyl sulfonic acid and six grains of potas- The developer is thus ready for use.

In the above example sodium sulfite may be replaced by potassium sulfite, sodium pyrosulfite, or potassium pyrosulfite or the like.

Having thus described our invention and in what manner the same is to be performed, What we claim as new, and desire to secure by Letters Patent, is

1. The herein-described process of developing photographic pictures, which consists in subjecting them to the action of a solution containing amido-o-oxybenzyl sulfonic acid, substantially as hereinbefore described.

2. The process of developing photographic pictures which consists in subjecting them to the action of a solution containing amido-ooxybenzyl sulfonic acid, a preservative and an accelerator, substantially as hereinbefore described.

3. The process of developing photographic pictures which consists in subjecting them to the action of a solution containing amido-ooxybenzyl sulfonic acid, a sulfite and an alkali carbonate, substantially as hereinbefore described.

In testimony whereof we have signed our names in the presence of two subscribing witnesses.

FRIEDRICH FISCHER. HUGO GUNTRUM.

Witnesses:

O'rro KONIG, J. A. RITTERSHAUS. 

